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Niacin

Evidence Fact Sheet

Nicotinic Acid · Vitamin B3 acid form

Niacin (nicotinic acid, vitamin B3 acid form) is a GPR109A agonist and NAD+ precursor studied at RDA doses (14-18 mg/day) for deficiency prevention and at gram-range prescription doses (500-2000 mg/day) for lipid modulation. Large RCTs and meta-analyses show no cardiovascular event benefit on a statin background.

Also known as: Nicotinic Acid · Vitamin B3 (acid form) · Vitamin PP (acid form) · Niaspan (Rx ER form)

Overview

Niacin (nicotinic acid, vitamin B3 in its acid form) is an essential water-soluble vitamin that serves as an NAD+ precursor via the Preiss-Handler pathway and, at pharmacologic doses, acts as an agonist of the GPR109A (HM74A) receptor on adipocytes, shifting lipoprotein metabolism (raising HDL, lowering triglycerides). Nutritional research interest centers on deficiency prevention (RDA 14-18 mg/day), while a large body of cardiovascular trial evidence used gram-range extended-release prescription forms (500-2000 mg/day, e.g. Niaspan). Regulatory status: FDA GRAS as a vitamin B3 source (with a separate Rx pathway for hyperlipidemia); EFSA authorizes six vitamin B3 health claims under Reg 432/2012; ANVISA lists "niacina" with four functional claims under IN 28/2018; China treats it as an established nutrient under GB 14880. A non-prescription tolerable upper intake level of 35 mg/day applies (NIH-ODS), with flushing common above ~50 mg/day.

Mechanism of Action

HM74A/GPR109A agonism · NAD+ precursor · Lipid management (HDL+ / TG-) · Adiponectin-mediated insulin sensitivity

Body systems: METABOLISM · Cardiovascular · Skin & Connective Tissue

Evidence-Based Benefits

Each benefit below is anchored to a specific PubMed-indexed study. Effect sizes, sample sizes, and p-values are reported as published; no values are inferred. Honest negatives and null results are kept alongside the positive findings, and disease-research populations are described as such — Niacin is not characterized as a treatment for any disease.

Cardiovascular Event Prevention (Pooled Trials)

Null / no benefit Meta-analysis supported
  • RR 1.05 (0.97-1.12)overall mortality · n=35,543
  • RR 1.02 (0.93-1.12)CV mortality · 5 studies
  • 23 RCTs39,195 participants

This Cochrane meta-analysis of 23 randomized trials found no reduction in overall mortality or cardiovascular mortality with niacin, and the authors concluded that benefits in preventing cardiovascular disease events are unlikely. Participants on niacin discontinued treatment significantly more often due to adverse effects. This is an honest negative finding for the gram-dose lipid-modifying use of niacin.

Reported effect: Overall mortality RR 1.05 (95% CI 0.97-1.12; n=35,543; 12 studies); CV mortality RR 1.02 (95% CI 0.93-1.12; n=32,966; 5 studies); 23 RCTs, 39,195 participants total

“niacin did not reduce overall mortality (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.97 to 1.12; participants = 35,543; studies = 12) ... cardiovascular mortality (RR 1.02, 95% CI 0.93 to 1.12; participants = 32,966; studies = 5)”

Source: PMID 28616955 · Schandelmaier 2017 · Cochrane Database Syst Rev

Add-On to Statin Therapy (AIM-HIGH RCT)

Null / no benefit RCT supported
  • HR 1.02 (0.87-1.21)primary endpoint · P=0.79
  • 3,414participants randomized
  • 35 → 42 mg/dLHDL at 2 years

In the AIM-HIGH trial, adding extended-release niacin to intensive statin therapy raised HDL and lowered triglycerides and LDL, yet produced no incremental clinical benefit; the trial was stopped early for lack of efficacy after a mean 3-year follow-up. A clear honest negative for niacin on a statin background.

Reported effect: Primary endpoint hazard ratio 1.02 (95% CI 0.87-1.21, P=0.79); events in 282/niacin (16.4%) vs 274/placebo (16.2%) of 3,414 participants; HDL rose from 35 to 42 mg/dL, triglycerides fell from 164 to 122 mg/dL

“The trial was stopped after a mean follow-up period of 3 years owing to a lack of efficacy ... no incremental clinical benefit from the addition of niacin to statin therapy during a 36-month follow-up period.”

Source: PMID 22085343 · AIM-HIGH Investigators 2011 · N Engl J Med

Major Vascular Events + Safety Signal (HPS2-THRIVE RCT)

Null / no benefit RCT supported
  • rate ratio 0.96 (0.90-1.03)major vascular events · P=0.29
  • +3.7 ptsdiabetes-control disturbance · P<0.001

In the largest niacin outcomes trial (25,673 patients), extended-release niacin plus laropiprant had no significant effect on major vascular events and was associated with significant excesses of serious diabetes-control disturbances, new diabetes, infection and bleeding. This honest negative, with a clear harm signal, anchors the caution around gram-dose niacin.

Reported effect: Major vascular events 13.2% vs 13.7%, rate ratio 0.96 (95% CI 0.90-1.03, P=0.29); serious diabetes-control disturbance absolute excess 3.7 pts (P<0.001), new diabetes +1.3 pts, infection +1.4 pts, bleeding +0.7 pts (all P<0.001)

“Assignment to niacin-laropiprant, as compared with assignment to placebo, had no significant effect on the incidence of major vascular events (13.2% and 13.7% of participants with an event, respectively; rate ratio, 0.96; 95% confidence interval [CI], 0.90 to 1.03; P=0.29).”

Source: PMID 25014686 · HPS2-THRIVE Collaborative Group 2014 · N Engl J Med

Lipids and Glucose in Type 2 Diabetes (Pooled)

Meta-analysis supported
  • +0.27 mmol/L (0.24-0.30)HDL · P<0.001
  • -0.39 mmol/L (-0.43 to -0.34)triglycerides · P<0.001
  • +0.085 mmol/Lfasting glucose · long-term

This meta-analysis of randomized trials in type 2 diabetes found niacin raised HDL cholesterol and lowered LDL and triglycerides, but also modestly increased fasting plasma glucose during long-term treatment. The result illustrates the trade-off between niacin's lipid effects and its impact on glycemic control.

Reported effect: HDL +0.27 mmol/L (95% CI 0.24-0.30, P<0.001); LDL -0.250 mmol/L (95% CI -0.47 to -0.03, P<0.05); triglycerides -0.39 mmol/L (95% CI -0.43 to -0.34, P<0.001); long-term fasting glucose +0.085 mmol/L (95% CI 0.029-0.141, P<0.05)

“HDL cholesterol: 0.27 (95% CI: 0.24 to 0.30; P < 0.001) mmol/L ... Triglycerides: -0.39 (95% CI: -0.43 to -0.34; P < 0.001) mmol/L ... Fasting plasma glucose (long-term treatment): 0.085 (95% CI: 0.029 to 0.141; P < 0.05) mmol/L”

Source: PMID 25306426 · Ding 2015 · Clin Nutr

Terminal Metabolite (4PY) and Vascular Inflammation

Emerging / indexed
  • HR 1.89-1.994PY · 3-year MACE
  • 2,331 / 832US / European cohorts
  • VCAM-1induced in mice

This Nature Medicine study reported that the terminal niacin metabolites 2PY and 4PY were associated with increased 3-year cardiovascular event risk across two validation cohorts, and that 4PY specifically induced VCAM-1 and leukocyte adhesion to vascular endothelium in mice. It offers a mechanistic explanation for why excess niacin may not benefit, and could even add to, residual cardiovascular risk.

Reported effect: Adjusted hazard ratios 1.64-2.02 for 2PY and 1.89-1.99 for 4PY for 3-year MACE; US cohort n=2,331, European cohort n=832; 4PY induced VCAM-1 expression and leukocyte adherence in mice

“Serum levels of the terminal metabolites of excess niacin, N1-methyl-2-pyridone-5-carboxamide (2PY) and N1-methyl-4-pyridone-3-carboxamide (4PY), were associated with increased 3-year MACE risk ... Treatment with physiological levels of 4PY, but not its structural isomer 2PY, induced expression of VCAM-1 and leukocyte adherence to vascular endothelium in mice”

Source: PMID 38374343 · Ferrell 2024 · Nat Med

Adverse Effects of Oral Niacin/Nicotinamide (Overview of Reviews)

Meta-analysis supported
  • 14 reviewsoverview of reviews
  • <1500 mg/dayNAM monitoring threshold

This overview of 14 reviews catalogued the adverse-effect profile of oral niacin and nicotinamide, reporting gastrointestinal upset, liver dysfunction, flushing/vasodilatory effects, skin rash and fatigue. The authors noted routine adverse-effect monitoring may not be indicated for oral nicotinamide below 1500 mg/day, contextualizing tolerability across the studied dose range.

Reported effect: Overview of 14 reviews; adverse effects included GI upset, liver dysfunction, flushing, skin rash and fatigue; routine monitoring possibly not indicated for oral NAM under 1500 mg/day

“Oral niacin and NAM were associated with a range of AEs including GI upset, liver dysfunction, flushing/vasodilatory effects, skin rash and fatigue.”

Source: PMID 40999226 · Young 2025 · Eye (Lond)

Dosage (research context · not a recommendation)

14-18 mg/day RDA (B3 deficiency prevention) · 500-2000 mg/day Rx ER Niaspan (Tier C · prescription only)

Regulatory Status · 4 Markets

US · FDA
GRAS (vitamin B3 acid form low dose) · Rx Niaspan for hyperlipidemia
EU · EFSA
Reg 432/2012 authorized health claims · 6 niacin claims (vitamin B3 family)
CN · China
Established nutrient — SAMR-permitted vitamin B3 source (nicotinic acid form) under GB 14880 food-fortifier standard (NRV 15 mg/day); usable in general food fortification and health-food registration. High lipid-modifying doses (1-3 g/day) fall outside routine supplement use and trigger health-food or drug controls.
BR · ANVISA
IN 28/2018 Anexo V "niacina" · 4 functional claims (pele · mucosas · metabolismo energético · metabolismo de proteínas/carboidratos/gorduras) · UL 35 mg/day non-prescription

Authorized Claims

EFSA — “Niacin contributes to normal energy-yielding metabolism” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2009;7(9):1224)

EFSA — “Niacin contributes to normal functioning of the nervous system” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2009;7(9):1224)

EFSA — “Niacin contributes to normal psychological function” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2010;8(10):1757)

EFSA — “Niacin contributes to the maintenance of normal mucous membranes” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2009;7(9):1224)

EFSA — “Niacin contributes to the maintenance of normal skin” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2009;7(9):1224 + 2010;8(10):1757)

EFSA — “Niacin contributes to the reduction of tiredness and fatigue” (Reg 432/2012 Annex · authorized health claim · EFSA Journal 2010;8(10):1757)

ANVISA — “A niacina auxilia no metabolismo energético.” (IN 28/2018 Anexo V · alegação funcional autorizada)

ANVISA — “A niacina auxilia no metabolismo de proteínas, carboidratos e gorduras.” (IN 28/2018 Anexo V · alegação funcional autorizada)

ANVISA — “A niacina contribui para a manutenção da pele.” (IN 28/2018 Anexo V · alegação funcional autorizada)

ANVISA — “A niacina auxilia na manutenção de mucosas.” (IN 28/2018 Anexo V · alegação funcional autorizada)

Safety

Flushing common at > 50 mg/day acute · hepatotoxicity at sustained > 3 g/day · UL 35 mg/day (NIH-ODS) for non-prescription · Rx Niaspan AIM-HIGH 2011 (PMID 22085343) + HPS2-THRIVE 2014 (PMID 25014686) showed no incremental benefit + adverse signal on statin background

Goals: heart-health · longevity-stack

Lifestyles: senior-60-plus

References

PubMed-indexed citations anchoring the benefit findings above. Effect sizes are reported as published.

  1. PMID 28616955 · Schandelmaier 2017 · Cochrane Database Syst Rev — Cardiovascular Event Prevention (Pooled Trials)
  2. PMID 22085343 · AIM-HIGH Investigators 2011 · N Engl J Med — Add-On to Statin Therapy (AIM-HIGH RCT)
  3. PMID 25014686 · HPS2-THRIVE Collaborative Group 2014 · N Engl J Med — Major Vascular Events + Safety Signal (HPS2-THRIVE RCT)
  4. PMID 25306426 · Ding 2015 · Clin Nutr — Lipids and Glucose in Type 2 Diabetes (Pooled)
  5. PMID 38374343 · Ferrell 2024 · Nat Med — Terminal Metabolite (4PY) and Vascular Inflammation
  6. PMID 40999226 · Young 2025 · Eye (Lond) — Adverse Effects of Oral Niacin/Nicotinamide (Overview of Reviews)

Frequently Asked Questions

1. Does niacin reduce heart attacks or cardiovascular deaths?

The strongest pooled evidence says no for the gram-dose lipid-modifying use. A Cochrane meta-analysis of 23 randomized trials (39,195 participants) found overall mortality RR 1.05 (95% CI 0.97-1.12) and cardiovascular mortality RR 1.02 (95% CI 0.93-1.12), concluding cardiovascular benefit is unlikely. These are research findings in studied populations, not treatment guidance.

2. If niacin improves HDL and triglycerides, why doesn't it help on a statin?

Two large RCTs answered this directly. In AIM-HIGH, niacin raised HDL (35 to 42 mg/dL) yet gave a primary-endpoint hazard ratio of 1.02 (95% CI 0.87-1.21, P=0.79) and was stopped early for lack of efficacy. In HPS2-THRIVE (25,673 patients), the rate ratio for major vascular events was 0.96 (95% CI 0.90-1.03, P=0.29). Favorable lipid changes did not translate into fewer events on a statin background.

3. What are the main safety considerations seen in the research?

In HPS2-THRIVE, niacin was linked to a significant excess of serious diabetes-control disturbances (+3.7 percentage points, P<0.001) plus more new diabetes, infection and bleeding. An overview of 14 reviews catalogued GI upset, liver dysfunction, flushing, skin rash and fatigue. The card also notes flushing is common above roughly 50 mg/day and a non-prescription upper limit of 35 mg/day.

4. Is there a mechanism explaining the lack of benefit?

A Nature Medicine study (Ferrell 2024) reported that niacin's terminal metabolites 2PY and 4PY were associated with higher 3-year cardiovascular event risk (4PY hazard ratios 1.89-1.99), and that 4PY induced VCAM-1 and leukocyte adhesion to blood-vessel walls in mice. This is an emerging, partly preclinical mechanistic finding, not a clinical recommendation.

Last evidence review: 2026-06-02

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